Elemental Stacked Image Sensor

Abstract

Provided herein is a novel stacked pixel design for image sensor applications. The stacked pixel designs may comprise a first and second wafer, wherein the first wafer is an elemental wafer comprising a photodiode and minimal additional components, such that material selection and processing steps of the first wafer may be optimized for the creation of a high quality photodiode. The second wafer comprises components necessary for the readout and reset of the photodiode on the first wafer.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of priority to U.S. Provisional Application Ser. No. 61 / 885,342, entitled “Elemental Stacked Image Sensor,” filed Oct. 1, 2013, and to U.S. Provisional Application Ser. No. 61 / 926,607, entitled “Elemental Stacked Image Sensor,” filed Jan. 13, 2014, the contents of both of which are hereby incorporated by reference.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT[0002]Not applicable.REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISK APPENDIX[0003]Not ApplicableBACKGROUND OF THE INVENTION[0004]As CMOS image sensor technology has progressed, pixel size has become increasingly smaller. Meanwhile, four- and five-transistor designs have become common. To accommodate the additional components required for low-noise, high resolution imaging, active pixels have a smaller photosensitive area. Additionally, the close proximity of the components to each other in the pa...

AI Technical Summary

Benefits of technology

[0014]Provided herein is a new design concept which meets the aforementioned needs and provides the art with simpler, high-quality photosensor designs, while simplifying manufacturing protocols. The invention encompasses the use of a stacked pixel, comprising a top layer with a photodiode and transfer gate, and a bottom layer comprising circuitry for storing signals, reading signals out, and resetting components. This advantageously allows the use of high quality mate

Problems solved by technology

Additionally, the close proximity of the components to each other in the packed space requires complicated architecture and complex fabrication schemes, in order to avoid leaks, electrical crosstalk, parasitic capacitance, and other complications that result from closely spacing components and wires on a wafer.

Dark current is an especially problematic issue in crowded pixel architectures.

The dark current and dark current distribution of CMOS image sensors sets an upper limit to the performance of these devices for night vision, scientific, and digital still camera applications.

However, the power consumption and cost required for cooling techniques,

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